Charge forming device



Dec. 12, 1950 E. o. WIRTH ETAL 2,533,863

CHARGE FORMING DEVICE Filed June 9, 1944 2 Sheets-Sheet l I ATTORNEY Dec. 12, 1950 E. o. WIRTH ETAL CHARGE FORMING DEVICE 2 Sheets-Sheet 2 Filed June 9, 1944 Patenteri Dec. 12, 1950 "UNITED STATES PAT signers toB endiX Aviatiori eorporation,

ScutirBendflnd a, etr oration ofiDel'aWizre Application June 9, 1e44,""seria;i N; 5393a? 14 Claims.

K Thisiiiv'ntioii relates to charger-arming de- Vices for"iritifial boifibilstion ng'ifies 'afid particiilarly to rheafis for supplying fan auxiliary 'fiilid to the hgifie tb' prevent fi eti')'nBItin "and ta; met-ease the'pe'wer thereof. 7 v Internalcombustion engines have a'tehdeney to overheat and iese-p wer under" certain -torifi i tifis aswh'eri operating at high $156655 arid/O1 iiri'ir "heavy loads. Numerous "mea s; have been protested to 'ov'e'i'cbine the ab-ove difiiulti'es, one of' siibh means-being thaddifiiofi off'fi'l'el toilhe W 'filiiituf at high "speeu's and loadywhith f results m a mixtu e'rriu euricrrer than" that refi'uire'aTffl "etfficierit efi'gir'fe "aeration-both asto "eeonorfi' "fidpowi', Anotherin' eans proposed 'fbr ever'ca in}; the abb'veiiifiic'uitie's, as Well "as "detenatibn Whih occurs 'lir'id'e'i" Various "v'vellown conditions, is the adding" of auxiliary f'fiujid s ch water, aiebhm 'or the 1i1e"t0""the fuel mixture, but the venues fsystemsrer arr-m I -in; and ebfltr ollihg the deli'ilfy'fo fSflbh'huXiliary fluids have not'be'en'eiitirely satisfactory for various reasons and itis" therefore an ime portant bbli'ect of thebrejseht' ifivfitibnto'fp'i'o- I yide means for accurately i supplying "ail ir'il'iary fluid to the ruermixture'in ab r dafi'e iii/1th the requirements of the en'ginethr'ouglioi t'it's'range of operation to overcbmethe abate difiit iulties The invention may be used in connection with a float type of carbur e tor or -pjre'ssure'tsipe' of carburetor and the auxiliary fiuid may be Hischarged into the intake passage from m inc}ependent nozzle or; it maybe dischargei into the fuel conduit anterior to the discharge nozzle so that thefuel'and auxiliary ffiuid will be mixed -;i;n--s'aid conduit and discharged into the inductiqn' passage in its rnixed condition. 7 v I-t -isfurther contemplated 7 that theauiilia-ry-fluid be supplied and; delivered under superatmospheric pressure and that the auxiliary,

-fluidbe metered while being maintained} under 7 such- :pressure; therebeing meansiorcontroling the :pressure Ofthe unmetered fiuid and the pr-essureof the metering --f1uid, the mean for controlling thepressure of the metered 'fluidv being; operable independentlyof the means for controlling the pressure of the unmetered fluid.

It is another-purposeof the-invention to control the pressure of the unmeteredfluidin'ac- I cordance with said unmeteredfiuid :pressure and an auxiliaryfiuid supply reservoir which ismain venturrpressure, "ariw'pressure or thesoir'rbeof air supplied tdtheearbufetor; and the control for the auxiliary-fluid may inbiude eon- "ti'bl iin'it's sirniiafi'to' the eontroi units of the pressure "carburetor, the corresponding cham- 'be'rs'bf thea'uiiiliafy *fluid'controlunitbeingsubjecteei to substantiall 'the'same pressuresiwsubijtaritiaily the same" way as" thevarious'ehambers or the carburetor, thereby providing a correlated and the aiix'iliar'yfiuid.

The 'iiivention""ffiither"contemplates that""the auiiliary fluid be added "throughout "substantiahy "the entire range of 'engine'pperation.

-Other objects and eiivantageswfthe inven- 'tion will be readily" apper'entto "one s'k'illedfin the 'art from the following descriptiontakemin connection 'viiththe accompanying ."drawings which represent preferred" embodiments. "'ABter considering these embodiments, "Skilled persons a will understand "that manywfiatmns may be maiie Without fiepar'ting"from' the, principles "disclosed; and we contemplate the' eniployrr'ientof any structure, arrangements, or"modeso'f operationlthat are properly withinthe' scope" o'fthe appended "claims.

"In the drawings: Figure "1' 'is a fiiagrammatic sectional view' of a charge forming Lsystem emboiiying" the invention; and

'Figu'rfl is aiiiagramrnatic' sectional "view of a modified emb'ofirrient. Whi1ethe' ihveii'fibn has b'een illiistl'a td and fiescribed 'her ein in connection with cafb'ufetors ier aircraftengihes, it "to'i'be"'untierstoottthat it may also be' used in cbniiebtion with carburetorsifor other automdtwe v'e'hiles such; as automobile, bus and triik carburetors andilthe "like.

'Pt'ferring'lfirst" to Figure 1 "there 'isdis'elosed ef'fioat type carburetor suh as maybe-useiii on aircraft enginesjsaid car'buretor, .as'shown, nomprisingta body ifl havingian induction e pa'ssage 5 l 2 therethroughand including an .a'ir entrance i t and aunigrture outlet J S attached .to; the in- --tak e manifold I if of an internal i eor'ribusition enginebyany -we11- known/means. i ,unturi I8 is disposed in the induction passage and fuel is discharged into said venturi by a fuel nozzle 20 supplied with fuel from a float chamber or fuel reservoir 22 having the usual float mechanism 24 for maintaining a substantially constant level of fuel in said chamber 22. Idling passages 26, 28 and 29 supply idling fuel to a slot like idling port 39 adjacent one edge of a throttle valve 32 which controls the discharge of mixture from the outlet l6, there being an idling tube 34 in the passage 28. The passage 29 and port 39 are formed in a rotatable plug 38 which may be rotated by means of a lever 46 for varying the angularity of said idling port 36 with respect to the adjacent edge of the throttle valve when in the idling position. The air inlet I4 may be supplied with atmospheric air or, if desired, said inlet may be supplied with air from a supercharger delivering said air at superatmospheric pressure.

In the present disclosure the auxiliary fluid will be considered to be water although, alcohol, ethyl fluid, exhaust gases, or other anti-detonation fluid may be used and the auxiliary fluid or water may be supplied from a reservoir 42 having a conduit 44 leading to a control unit indicated generally at 46. The conduit 44 is connected with an inlet chamber 48 of the control unit 46, said chamber 48 having a port 59 communicating with a chamber 52 and controlled by a valve 54. A relatively light spring 56 disposed in chamber 48 yieldably urges the valve 54 in a closing direction, said valve having a stem 58 adapted to be engaged by the head of a rivet 60 centrally attached to a preformed flexible diaphragm 62 clamped between casing members 64 and 66 of the unit 46, said diaphragm separating the chamber 52 from a chamber 68 which is connected with the air inlet of the carburetor by a conduit 16. A spring 12 is disposed in chamber 68 and reacts between one wall of the casing member 66 and a spring retainer washer 14 secured to the diaphragm 62 by the rivet 66. A passage 16 connects the chamber 52 of unit 46 with a chamber 18 in a control unit indicated generally at 80, there being a metering restriction 82 provided in the passage '16 between the unit 46 and the unit 89. The control unit 46 controls the pressure of the unmetered water, that is,

it controls the pressure of the water on the upstream side of the metering orifice 82, and the control unit 89 controls the metered water pressure or the pressure thereof on the downstream side of the metering jet 82. Water from the chamber 18 of unit 88 is discharged into the mixture chamber of the induction passage from a nozzle 84 posterior to the throttle valve, said nozzle being connected with the chamber 19 by conduit 86 and, if desired, the discharge end of the nozzle 84 may be beveled with the bevel facing downstream relative to the fluid flow in the induction passage as shown in Figure l, for increasing the suction in the nozzle 84 relative to the suction in the mixture chamber posterior to the throttle. Discharge of fluid from chamber 18 is controlled by a valve member 88, of any suitable well known type, cooperating with a port 89 for controlling the flow of water from chamber I8, said valve member 88 being secured to a preformed flexible diaphragm 99 forming one wall of the chamber 18 and separating said chamber from a chamber 92 which is connected to the throat of the venturi [8 by means of a conduit 94. A spring 96 is provided in chamber 92, and one end of said spring is received in a spring retainer 98 secured to the diaphragm by a rivet I00, said spring being adapted to urge the diaphragm to the left in a direction to close the valve 88. The other end of the spring is received in an adjustable spring retainer I02 which is movable longitudinally of the spring by an adjustment screw I94 for adjusting the pressure of said spring on the diaphragm 90. Water in the tank 42 is subjected to and maintained under superatmospheric air pressure, preferably approximately three pounds per square inch, by an air pump of any suitable character, indicated generally at I06, said air under superatmospheric pressure delivered to the tank through a conduit I98 and preferably to the upper portion of said tank.

Operation The operation of the device shown in Figure 1 is as follows:

The pressure of Water supplied to the chamber 52 of unit 46 on the upstream side of the metering jet 82 is controlled by the valve 54 which is urged in the opening direction by the spring 12 and the pressure of air from the source of air supplied to the intake of the carburetor, and in the closing direction by unmetered water pressure in chamber 52 which acts on the diaphragm in opposition to the pressure of spring 12 and said air pressure. Thus the pressure of unmetered Water delivered by the unit 46 is controlled by spring 12, the pressure of air supplied to the carburetor and unmetered water pressure. The metered water pressure is controlled independently of the unit 46 by the metered water pressure, the pressure of spring 96 and the fluid pressure in the venturi I8,'the spring 96 being so calibrated that valve 88 closes the discharge port 89 when the pressure in chamber 92 is atmospheric and opening of the valve 88 is effected by Venturi suction when the engine is operating, preferably beyond its idling range.

Preferably the spring 96 is so calibrated that the valve 88 is opened at a very small Venturl depression below atmospheric pressure so that as soon as the throttle valve 32 is opened off idling position water will begin to flow into the induction passage from the nozzle 84 and the quantity of water delivered to said induction passage will continue to flow throughout the entire throttle range and reach a maximum when suction in the venturi [8 reaches the maximum. It has been found that the addition of auxiliary fluid. throughout substantially the entire range of engine operation tends to maintain the engine operating temperatures at all times at the proper point for most efficient operation and to thus increase the power of the engine. This arrangement has also been found to prevent detonation.

As the water supplied to the fuel mixture takes the place of the fuel heretofore supplied to said mixture in excess of that required for maximum economy and efiiciency, it will be apparent that the present invention effects a substantial saving of fuel. Another advantage of the present invention is that, as it prevents overheating of the engine and maintains the operating temperature at the desired relatively low value throughout its operating range, heavier, less volatile and cheaper fuels may be used.

With reference to Figure 2, there is shown a pressure type of carburetor having a main body member I it which contains an induction passage I I2 therethrough and includes an air inlet I I4 and an outlet I IS, the air inlet being provided with an outer surface H8 to which an air scoop (not I3! in the induction passage posterior to the vehturi and .is adapted to be manually actuated r ii'if giredr.

y be' used iri iii of rdd '|5'8,'-""r1 I inthe reejess the rivet I'Sfaiiid'seiid 'pin eraibls'i pr6iii'died with a round nd 'tdfforrh an gill'irly djii'stable" o'rie-w'aydhnef'tidfi betw the" diaphragm whereby {slight 'mis'alignifieii of 52pm diaphragm's may-be ac'dtfiihodated witl'idut' binding; This coilstrubtiqn'alsdgreatly falilitifes i assembly and di'se ssembliy pf the'conti or'unig 32 Chamber l ii! *is provided with al'fuel iziletpbrfi' controlled by-a val'v': I60 and rceivsfuelfromz asource of fue'I' under pressure; such" as a "fuel" pump' (not shown) through a pipe 182. The valve I60 has a pin-like extensio'n" projectirigifito th chamber I43 in1 p'osition to be engagedby the head of rivet I52 whereby movementof theiidiaa phragms torthe right"opehs'itheivalve. .;,A spring I6 urgesthe valve ,to; its closed 'iposi-tibn ;a.r1,d v j springv E 65 is meunted' atone endiof the chamber M an a t fre ndi eceived ntaispring amer po n .QLa "lever lfi8qp votal ytmnun sd.

232 of sleeve 225 is provided with an annular flange 231 which may be spaced to the right of spring retainer 23I under certain operating con-- ditions and is adapted to move through an opening 238 in wall 233 when the sleeve 225 is moved to the left under the influence of diaphragm 206. Further movement of the sleeve to the left is then yieldingly resisted by spring 234. The movement of the rod 22'! and cross-bar 226 to the left is limited by stops 239 integral with the casing I35 at such times as the throttle is opening beyond its idling or near idling positions andthe diaphragm 206 is urged to the left by the pressure of fuel in the chamber 200. The sleeve 225 limits such movement of the diaphragm and when the throttle is opened a limited amount beyond the idling or near idling position the fuel pressure in chamber 200 and the suction in chamber 208 moves the valve 2I0 to the left only sufiiciently far to withdraw the step 2 I 4 from the orifice 2I8, the shoulder 23? now abutting against the spring retainer 23! so that the sleeve 225 is held against further leftward movement by the spring 234. During high power operation, how-' ever, the unmetered fuel pressure in chamber 200 and the low Venturi pressure in chamber 208 create a sufficient pressure differential across the diaphragm 206 so that the spring 234 is compressed and the step 2I6 at the end of valve 2I0 is completely Withdrawn from the orifice 2 I8. H

Thus during idling, with the parts as shown in Figure 2, the step 2E4 cooperates with the orifice 2 l8 to limit the area for fuel flow. As the throttle is opened through the idling range the valve 204, in the discharge nozzle assembly I36, which,

is separated from a chamber 250 by a preformed annularly grooved diaphragm 252 operably connectedto a fuel outlet valve 254 and urged to the right in a direction to close the valve by a spring 256 arranged to be variably loaded by an adjustment screw 258, said chamber 250 being connected to the Venturi annulus I22 by the passage H5. The stem of valve 254 is of triangular cross section or otherwise relieved to permit fuel to flow therepast and is slidable within the nozzle bar or member 260. In this arrangement the valve 254 is not fixed to the diaphragm 252 but is maintained in abutting relation therewith by means of a light spring 262 which constantly urges the valve 254 to the left. This arrangement eliminates any tendency for the valve to bind in its valve guide and seat member 264 as a result of misalignment between the diaphragm and the emulsion thus produced is discharged from the nozzle. A tube 214 is disposed about a portion of An acceleration pump, indicated generally at:

362, may be provided if desired, and includes a suction chamber 304 connected through pipe 306 withthe induction passage H2 posterior to the throttle. A diaphragm 308 urged to the right by a spring 3l0 separates the suction chamber 304 from a fuel chamber 3I2 connected through a pipe 3l4 with the passage I98. During periods of high engine suction the diaphragm 308 is moved to the left and the fuel robbed from the passage I98 is drawn into the chamber 3I2. Upon a loss in engine suction, as upon acceleration, the spring 3l0 forces the diaphragm to the right and pumps fuel from chamber 3I2, through the unit I34 and to the nozzle chamber 204 thereby temporarily richening the mixture.

OPCTdtiOTZ The operation of the device disclosed in Figure 2 is as follows:

Assuming the carburetor has not been filled with fuel and the idle cut-off plunger I10 is in its lower position as shown, the spring I66 will urge the diapln'agms to the right and open the valve I60. Fuel under pressure supplied to pipe I62 enters and fills chamber I40 and flows through the unit I34 and pipe 202 to the chamber 204'. As the pressure in chamber I40 increases it acts against the diaphragm I46 and tends to com press spring I66 whereby the valve 560 tends to close. Fuel under pressure supplied to chamber 204 acts on diaphragm 252 and tends to open- The screw 250 is normally adjusted valve 254. to compress spring 256 to such a point that a slightly lower pressure is required in chamber 204 to open the valve 254 than is required in chamber screws 258 preferably is adjusted to permit valve- 254 to open at a pressure somewhat less than the closing pressure for valve I60, it will be apparent that by screwing the adjustment screw 258 in or out the pressure in chamber 204 required to open valve 254 may be made greater than, equal to or less than the pressure required in chamber I40 to permit the valve I60 to close. It will also be apparent that the actual value or degree of the fuel pressure will be determined by the strength of the springs I66 and 256, the pressure required being greater as the strength of the spring is increased.

It has generally been found desirable to adjust the discharge nozzle spring 256 sufliciently weaker, in proportion to the area of the diaphragm 252, than the spring I66, in proportion to the area of diaphragm I46, so that at idle an excessively rich mixture is obtained, and then to decrease the richness of the idling mixture by decreasing the efiective area of the metering orifice 2I8 during idling operation. It is for this reason that the valve H0 and the rod 232 function to reduce the metering orifice area at idle. By con-,

trolling the rate at which the valve 210 is per-- mitted to move to the left as the throttle is I40 for sufiiciently compressing the spring I66 to permit the valve I60 to close. Oncethe ara'of diaphragm I opened from its idle position, any desired near idlingrichnesscanb'obtalined. "Duringoperation,assuming the area ratio of the'diaphragms 14B and" I48 is'equal to two,the regulator unit !32 functions tomaintain'a differential fuel pressure across the'metering unit I34 which is e'qual'to twice the venturi to entrance air differential pressure." For'example, a given decreasein' the pressure in the Venturi chamber IE2 is transmittedto'the' chamber E42, where it results in an equal increment'increase in the unmet'ered fuel pressure in chamber Hi9, and is transmitted to chamber md, where it results in an equal increment decrease 'in the metered iuel pressure; Consequently" the fuel n' e'tering diilerential pressure" is" increased in amount double the increase in the air differentiali "Sirhilarly agiven increase in the entering air pressure i the chamber [25 is transmitted to chamber I44 and since it is applied to the diaphragm 48 having twice the areao'f diaphragm i 4f6 ,"th e unmetered fuelpress'ur'e in chamber ""1 id is' increased an increment double the? increase in entering air pressure." Although the diaphragm (48 and M5 are shbwnhsihaving at o to-one"a rea relationship. may be of "any'oth'er desired area" ratio, "in case the Iuel'rn'etering 'difierential pressure will bejniaintained' atsoinelm lti'pl'e, otherthan two, of the air d ff tial pressure. *sd'r example jif the area "r di phragni 14ers three't'inies he' fuel differential times 'the'air g'ms Hi6 t ritia' re ual t t a clifier nt fa am" ventth fuel and air difierent al pressures are maintaihedin constant pronorti'onjand therefore'oonstantfuel to su -0' rtionirig is obt ned. v ,It is generally desirable to provide'the pilot with a manuallmiitture 'control so that he can vary the richness of the I'ni$ ture. between predetermined limits. .Fofr thispurpose the calibratedpassage I80, controlled by thetapered valve I82 is provided, which, with the valve closed corresponds to a rich setting. As the valve l82 is opened, air is bled from the air scoopchamber lflint' th Veiituri c amb r 2] whereb th difierential pressure. between these chambers is reduced an amount depending upon the extent .the valve I82 is opened. This in turn reduces the unmetered fuel pressurein chamber [401equired to maintain the diaphragm assembly in an equilibrium position, thus reducing the v fuel t s t Qfi iue fl w hrrei so hat twilino 9 tiuu o ru a are ul o r is itiona a t th 'is on lturne Q Toaqcomn is t end, the valve Q82 is moved outwardly beyond its full lean position 'to anidle cut ofi position at. W q h p ger 19 sz lqr e niuwa d y b a .lever35 iuatedbya acn sh pedq ler 35 on thevalve I82. .Thus the spring [66 iscom- 10 pressed and the light spring I64 is able to fully close valve I: v

emailin fluidcqntrq The auxiliary fluid or water control comprises a unit-generally indicated at 400, vfor con the'pressure of thefunmetered watch; and a indicated s e l ia 4.11 for ntro lin pressure of-therneteredivvater. Th ni ldnrc mnr es a es ns ha ing.) in ea pair ofdiaph sm 4fl a d4fl6, pre o ame si es a the res ect ve :diash f s 6 a 8 w ich rid t un t into"... ;hamb 40.8., Ma and m: Aux l r oflui'dsrwa r S supplied to the chamber 4H8through'acon 1ht 4l4 connected with a sypplyltank 4| 6 and a pres sure pump 4 I 8, interposed in conduit 414, delivers water to the unit"400"at-a substantially constant "pressure;which'pressurepreferably is substa tially the'same as the pressure of thefueld ered' by the fuelpump." "The fluid passes. fro Iv chamber i400- through a conduit 420-a3nd into-fa chamlcier 422inthe unit'402,there being a metei in'gorifi'ce 0'1 jet 424 disposed'in'the passage 42!) between the 'units 400" and 402: The How e: water into cha'mber408 is con'trolledby a"valve 426 'urgedi'in theclosing direction 'by spring and" having an" extension 430 adapted to be engaged by a rivet 4.32 "centrally disposed in the diaphragm 404. 'A'spring 434 'isdisposed in chamber- 4 I2'"'and" reacts between" one' wall said chamber and a spring-retainer 436 "secured "to'diap'l'iragm -406i-bva rivet 438 ---whicli: has an extension 440 on the opposite--side"ciftthedii f phragm received'in a'recessin rivet-"432? 'With this" arrangement sprir'ig"434- urges the diaphragm 406 to the:right and"the-pressure of saidspririg is transmitted to --tne-- diaphragm" 404 "through the extension"44'0'ofrivet 438; Movement'of the 'diaphragms" to "right is adapted-- to 'open waive 426 "against the pressure "of spring "428 which" is relatively light. conduit .442 *conriects' chantber 41 2" with the'ehamber 1 4'4" of "the carburetor and a conduit 444 connectschambei- 741D with the chamber -l42"'of*the carburetor?" Thusithe chambers 4 I;0"and 1'42'are subjected to the sa fie pressures; andeham'berS 4|2 and-144 'aresuhjectedto the samepressures: ".Metered'watenfromthe chamber 422 01' the unit "402 "is transmitted through" an orifice 423 to' a con'duit-446'and thence to the fuel passage 202 of'the carburetor,the"water aridtheffiiel mixing said passage and being deliveredito gethei'.,from the main fuel nozzle of; the carburetor. The unit 4'02 includes a diaphragm .448 preferably of substantially the same size" as? phragm252of;the'fuel control'nozzle unitil, a Diaphragm 448 separates chamber 422 ,from'a chamber 450 whichisconnected to the chamber 250 ofithe nozzle assembly unit I36 of'the-carburetor by means fQf. a"oonduit 452; Thu MW chambers 450 and 250 are subjected to sub an tially the same pressures. A spring. ,4 5 4 is disposed in chamber-I450 and is adapted tourge he diaphra m 448m n left in a direction a valve 456 with which thediaphrag m' is nested, theivalve 456' being adapted to so perof waterirom the'cha nber I22 into the; 446. .Meansfor adjusting the tension of 454 comprises a screw 458 having a spr n tamer 460 adjacent its. inner endand on 'whi' the spring454 is received. A spring 462'pi's vided i the chambe alm andu f a apt the ralv midd ri in e qpsnip 11 tion, said spring 462 however being relatively light and of less strength than the spring I54.

In the controls for the water the spring 434 is of such character that it is adapted to maintain the valve 428 in the open position; and the spring 454 is preferably of such character that it is adapted to maintain the valve 458 in the closed position when the engine'is inoperative or is operating in the idling range. Should it be desired to provide means for effecting closing of the valve 426 an arrangement similar to that used to effect closing of the valve I60 of the carburetor unit I32 may be used, or any other suitable mechanism may be employed.

Operation The operation of the units 400 and 402 is similar to the operation of the units I32 and I36 of the carburetor, the actuation and control of the valves .26 and 456 controlling the flow of water being correlated with the control of the fuel valves l6!) and 254 of the carburetor whereby auxiliary fluid begins to flow as the throttle valve initially moves from the idling range and said auxiliary fluid will continue to flow throughout the balance of the throttle range. That is the auxiliary fluid is delivered to the engine throughout its range except idling and is very accurately supplied in accordance with the requirements of "the engine under various operating conditions similarly to the supplying of fuel to the en ine, 'said fuel bein delivered before the auxiliary fluid begins to be delivered.

While the res ective diaphra ms of the fuel control units and the auxiliary fluid control units are shown and described as being of the same -size and the fuel and auxiliary fluid is described as being d livered at substantially the same pres sures, modifications of these elements may be made and various other elements of the respective control units may be modified to compensate for such modification so that the desired results mav still be obtained.

Moreover, while the invention contemplates the supplying of an auxiliary fluid for anti- -detonation purposes and the like as above de scribed it is to be understood that the arran ement may also be used to supply the engine with a plurality of fuels and it is thought that the invention and many of its attendant advantages will be understood from the foregoing description and though said invention has been illustrated and described in connection with several preferred embodiments thereof it will be apparent that various other changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the forms hereinbefore described being merely preferred embodiments.

We claim:

1. In a charge forming device: an air passage;

a venturi in the passage; a throttle in the passage posterior to the venturi; a fuel conduit leading from a source of fuel under pressure, to the passage; area restricting fuel metering means in the conduit; an inlet valve and an outlet valve in the conduit respectively anterior and posterior to the said means; means for controlling the inlet valve to regulate the unmetered fuel pressure and including a pair of diaphragms subjected to air pressure from the venturi and air passage anterior to the throttle; means for controlling the outlet valve to regulate the metered fuel pressure and including a diaphragm subjected to air pressure from the venturi and to only metered fuel pressure; means for supplying an auxiliary fluid to the air passage comprising a conduit leading from a source of fluid under pressure to the passage posterior to the throttle; area restricting fluid metering means in the conduit; an inlet valve and an outlet valve in the conduit respectively anterior and posterior to the said 1astmentioned means; means for controlling the inlet valve to regulate the uninetered fluid pressure including a pair of diaphragms subjected to air pressure from the venturi and air passage an terior to the throttle; and means for controlling the outlet valve to regulate the metered fluid pressure and including a diaphragm subjected to air pressure from the venturi; and means for controlling the auxiliary fluid being so constructed and arranged as to supply auxiliary fluid throughout substantially the entire engine operating range.

2. In a charge forming device for an internal combustion engine: an air passage; a throttle therein; a venturi in the passage anterior to the throttle; a fuel conduit leading from a source of liquid fuel under pressure to the passage posterior to the throttle; area restricting fuel metering means in the conduit, an inlet valve and an outlet valve in the conduit respectively anterior and posterior to the said means; means for controlling the inlet valve to regulate the unmetered fuel pressure independently of the metered fuel pressure and including a pair of diaphragms subjected to air pressure from the venturi and air passage anterior to the throttle and to only unmetered fuel pressure; means for controlling the outlet valve to regulate the metered fuel pressure independently of the unmetered fuel pressure and including a diaphragm subjected to air pressure from the venturi and to only metered fuel pressure; and means for supplying an auxiliary fluid to the air passage throughout substantially the entire engine operating range and including means responsive to air pressures in the venturi and the air passage anterior to the throttle.

3. The invention defined by claim 2 wherein the auxiliary fluid and the fuel are discharged from the same nozzle.

4. In a charge forming device for an internal combustion engine: an air passage; 2. throttle therein; a venturi in the passage anterior to the throttle; a fuel conduit leading from a source of liquid fuel under pressure to the passage posterior to the throttle; area restricting fuel metering means in the conduit; an inlet valve and an outlet valve in the conduit respectively anterior and posterior to the said means; means for controlling the inlet valve to regulate the unmetered fuel pressure independently of the metered fuel pressure and including a pair of diaphragms subjected to air pressures from the venturi and air passage anterior to the throttle and to only unmetered fuel pressure; means for controlling the outlet valve to regulate the metered fuel pressure independently of the unmetered fuel pressure, including a diaphragm subjected to air pressure from the venturi and to only metered fuel pressure; and means for supplying an auxiliary liquid to the air passage comprising a conduit leading from a source of auxiliary liquid un' der pressure to the passage posterior to the throttle; area restricting liquid metering means in the conduit; an inlet valve and an outlet valve in theliquid conduit respectively anten'or and posterior to said liquid metering means; means for controlling the inlet valve to regulate the unmetered liquid: pressure independently. oisthe metered-liquidpressure "and including a pair-of d-iapl'iragrns subj ected to air pressure.' from the venturi and air passageanterior to the. throttle and to only unmetered liquid: pressure; and means for controlling the last named outlet valve to regulate the metered liquid pressure independentlyof -tl-ieunmetered liquid pressure and including a diaphragm subjected to air pressure from the venturi and to only metered liquid pressure; the means for supplying auxiliary liquid being so constructed and arranged as tosupply auxiliary liquid; throughout substantially the entire engine operating range.

fifhe invention defined by claim wherein there is manualmeansior varying the iue l supto the air passage when the throttle valve s within the-idlingrange.

6 'ljhe invention defined-by elaim i wherein there-is manual mean -i'or ijegulatingthe supply; of fuel in accordance withthrottle pesiti'on throughout the throttle idlingrange; the means for supplying; the auxiliary liquid being so constructed and arranged as to begin supplying said liquid when the throttle opened beypnd its idling range.

7. The invention defined by claim 4 and including a manually operated mixture control element movable between a mixture rich and a mixture lean position, said mixture control element being adapted to modify the fuel-air and auxiliary liquid-air ratios.

8. The invention defined by claim 4 wherein the auxiliary liquid is supplied by a pump adapted to deliver said liquid under substantially constant pressure from a source of liquid supply.

9. The invention defined by claim 4 and including manual means for regulating the fuel flow throughout the idling range or" the throttle valve; and a power jet system controlled by fuel pressure posterior to the metering means and Venturi pressure, for increasing the richness of the fuel mixture under predetermined operating conditions of the engine; the means for supplying the auxiliary liquid being so constructed and arranged as to begin supplying auxiliary liquid when the throttle valve is moved beyond its idling range.

10. The invention defined by claim 4 wherein there is manual means for cutting off the supply of fuel to the air passage; the means for controlling the supply of auxiliary liquid including resilient means urging the outlet valve of the auxiliary liquid control to the closed position when the engine is inoperative.

11. In a fluid mixing device: an air passage having an inlet and an outlet; a valve controlling the flow of air through said passage; a venturi in the passage anterior to the throttle; a first liquid supply conduit leading from a source of liquid under pressure to the passage posterior to the throttle; area restricting metering means in the conduit; an inlet valve and an outlet valve in the conduit respectively anterior and posterior to the said means; means for controlling the inlet valve to regulate the unmetered liquid pressure independently of the metered liquid pressure and including a pair of diaphragms subjected to air pressures in the venturi and an air passage anterior to the throttle and to only unmetered liquid pressure; means for controlling the outlet valveto regulate the metered liquid pressure independently of the unmetered liquid pressure and including a diaphragm subjected to air pressure from the venturi and to only metered liquid 14 pressure;zandialductieraseqo d i uida se ie nomaisourceiunderl pressur t near 4 Pa' 'SEs'E posterior to the throttle; area restrictihgim er;- irismeansin the duct; .anz let valve an an. iet valyeiin theduct respe t v y anterior, and posterion to. the said; last-mentioned means;- means ifoncontrolling the inlet valve of the duct toregulateithe unmetered :liquid press there n independently .of-.-th.e meteredliquid pressure and including alpairiof diaphragms subjected to. sub} stantially-the samesair, pressures as the first mentionedapairof diaphragrns and toonly un; metenad liquide-pressurelin the duct; and means -for.. controlling the outletivalve. of the duct to regulate ithemetered liquid pressure therein indeperident-lybfithe unmeteredliquidpressure insaid ductand including-a diaphragm subjected-tosub stantially ithelsamelair pressure as the diaphragm controllingithe outletvalvein said conduitlandto only.-1neter'ed-.-liquidi pressure in said duct; the means :forrcontrolling the, liquids. being so, constructed and correlated that the flow of said flrst liquidotorthe ,ainpassage. will begin before the i-flowlof i saidlsecond .liquidbegins.

'12-. Eorusawitha charge forming device; having :a .thrott-le=contrplled air. intake passage ,pro-

vided with a venturi and means for supplying primary fuel to said passage, an auxiliary fluid injection device for supplying fluid to said passage including an auxiliary fluid supply conduit having a metering restriction therein, a valve for regulating the pressure of unmetered auxiliary fluid upstream of said restriction and pressure responsive means for controlling said valve subjected to the differential between air inlet pressure and unmetered fluid pressure, another valve for regulating the pressure of metered fluid downstream of said restriction, and pressure responsive means for controlling said latter valve subjected in a valve-opening direction to metered fluid pressure and Venturi suction and in a valve closing direction to calibrated resilient mechanical means, whereby the opening point of the latter valve with respect to degree of throttle opening may be readily predetermined, said valves functioning independently of one another to control unmetered fluid pressure independently of metered fluid discharge pressure.

13. For use With a charge forming device having a throttle-controlled air intake passage pro vided with a venturi anterior the throttle and means for supplying a primary fuel to said passage, an auxiliary fluid injection device for supplying an auxiliary fluid to said passage including an auxiliary fluid supply conduit having a metering restriction therein and terminating in a discharge nozzle arranged to inject auxiliary fluid into the primary fuel mixture posterior the throttle, a valve for regulating the pressure of unmetered fluid upstream of said restriction and pressure responsive means for controlling said valve subjected to the differential between air inlet pressure and unmetered fluid pressure, a calibrated spring urging said valve toward open position, another valve for regulating the pressure of metered fluid downstream of said restriction and pressure responsive means for controlling said latter valve subjected in a valveopening direction to metered fluid pressure plus Venturi suction and adjustable resilient means normally urging said second-named valve towards seated position, whereby the time of injection of auxiliary fluid may be adjusted to cover a predetermined range of throttle opening, said valves functioning independently of one another 15 to control the pressure upstream of said restriction independently of the pressure downstream thereof.

14. For use with a charge forming device having a throttle-controlled air intake passage provided with a venturi anterior the throttle and means for supplying a primary fuel to said passage, an auxiliary fluid injection device for supplying an auxiliary fluid to said passage including an auxiliary fluid supply conduit having a metering restriction therein and terminating in a discharge nozzle, a valve for regulating the pressure of unmetered fluid upsteam of said restriction and pressure responsive means for controlling said valve subjected to the differential between air inlet pressure and unmetered fluid pressure, another valve for regulating the pressure of metered fluid downstream of said restriction and pressure responsive means for controlling said latter valve subjected in a valveopening direction to metered fluid pressure and Venturi suction and in a valve-closing direction to calibrated resilient means, whereby the opening point of said second-named valve with respect to throttle opening may be readily predetermined,

said valves functioning independently of one an- 16 other to control unmetered fluid pressure independently of metered fluid discharge pressure and said nozzle being arranged in said air passage in a manner such as to produce a suction effect on the metered fluid flow thereto.

EMIL O. WIRTH. FREDERIK BARFOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 7 Name Date Re22,447 Hersey et a1 Feb. 29, 1944 1,746,358, Mock Feb. 11, 1930 2,002,483 Kimball May 21, 1935 2,252,415 Schwarz Aug. 12, 1941 2,233,021 Udale May 12, 1942 2,310,984 Mock et al Feb. 16, 1943 2,377,607 Bodine June 5, 1945 FOREIGN PATENTS Number Country Date 207,986 Great Britain Dec. 13, 1923 

